Abstract
The main objective was to evaluate the impact of nurse plant species commonly
found in Mediterranean areas (Lavandula dentata and Thymus satureoides) on microbial soil
functions, on the native inoculum potential of AM fungi involved in the rock phosphate
weathering and to measure the potential benefits to the growth of Atlas Cypress (Cupressus
atlantica G.), an endemic Cupressacea of Morocco. Soils collected from an old C. atlantica
forest and pre-cultivated with each of the target plant species (L. dentata and T.
satureoides). After 5 months of cultivation, they were uprooted and the treated substrate
was amended or not with Khouribga Rock Phosphate (KRP). Then pots were filled with the
soil mixtures and planted with one pre-germinated seed of C. atlantica. The results show
that pre-cultivation step with native mycotrophic plant species improves the mycorrhizal
soil infectivity, modifies soil microbial functionalities and increases the impact of rock
phosphate amendment on the C. atlantica growth. This low cost cultivation practice by
improving forest plant development and cultural soil quality constitutes a promising
ecological engineering tool to improve the performances of ecosystem restoration.

Key-words
Arbuscular mycorrhizas; Diversity; Nurse plants, Soil functional abilities; Rock
phosphate; Morocco

Highlights
- We test the impact of the nurse-plant syndrome on the rock phosphate solubilization
- Nurse plant pre-cultivation increases soil mycorrhizal infectivity and P solubilization
- This cultural practice could enhance the performances of afforestation programs